<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../js/vue.js"></script>
</head>
<body>
    <div id="app">
        {{msg}}
    </div>
</body>
<script>
    Vue.config.productionTip = false
    var vm = new Vue({
        el:"#app",
        data:{
            msg:"hello world"
        }
    })

    console.log(vm.$root === vm)
    console.log(vm.$el)
    console.log(vm.$options.data() === vm.$data)
    console.log(vm.$data)

</script>
</html>